title: Expression analysis of matrix metalloproteinase-9 in epithelialized and nonepithelialized apical periodontitis lesions.
abstract: OBJECTIVE
  The objective of this study was to determine the expression of matrix metalloproteinase-9 (MMP-9) in apical periodontitis lesions.
  
  
  METHODS
  Nineteen epithelialized and 18 nonepithelialized apical periodontitis lesions were collected after periapical surgery. After histological processing, serial sectioning, H&E staining, and microscopic analysis, 10 epithelialized and 10 nonepithelialized lesions were selected for immunohistochemical analysis for MMP-9 and CD 68. At least one third of each specimen collected was frozen at -70 degrees C for further mRNA isolation and reverse transcription into cDNA for real-time-PCR procedures. Geometric averaging of multiple housekeeping genes normalized MMP-9 mRNA expression level.
  
  
  RESULTS
  Polymorphonuclear neutrophils, macrophages and lymphocytes presented MMP-9 positive immunostaining in both types of lesions. When present, epithelial cells were also stained. The number and the ratio of MMP-9(+)/total cells were greater in nonepithelialized than epithelialized lesions (P = .0001) presenting a positive correlation to CD68(+)/total cells (P = .045). Both types of lesions presented increased MMP-9 expression (P < .0001) when compared to healthy periapical ligaments. However, no significant differences were observed for MMP-9 mRNA expression between ephithelized and nonephithelized lesions.
  
  
  CONCLUSIONS
  The present data suggest the participation of several inflammatory cells, mainly CD68(+) cells, in the MMP-9 expression in apical periodontitis lesions. MMP-9 could be actively enrolled in the extracellular matrix degradation in apical periodontitis lesions.
authors.affiliation: Department of Endodontics, Bauru Dental School, University of Sao Paulo, Brazil.
authors.forename: Everdan
authors.initials: E
authors.lastname: Carneiro
authors.forename: Renato
authors.initials: R
authors.lastname: Menezes
authors.forename: Gustavo Pompermaier
authors.initials: GP
authors.lastname: Garlet
authors.forename: Roberto Brandão
authors.initials: RB
authors.lastname: Garcia
authors.forename: Clóvis Monteiro
authors.initials: CM
authors.lastname: Bramante
authors.forename: Rita
authors.initials: R
authors.lastname: Figueira
authors.forename: Mari
authors.initials: M
authors.lastname: Sogayar
authors.forename: José Mauro
authors.initials: JM
authors.lastname: Granjeiro
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D004848:Epithelium / Q000201:enzymology; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis*; D008875:Middle Aged; D010485:Periapical Periodontitis / Q000201:enzymology* / Q000473:pathology; D016133:Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D020780:Matrix Metalloproteinase 9